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Compost-bedded pack barns for dairy cows

Quick facts

Compost dairy barns can be a good housing system for lactating dairy cows. The following are keys to success in compost barns:

  • Provide at least 100 square feet per Holstein cow and similar size breeds. Jerseys need 85 square feet per cow.
  • Use fine, dry wood shavings or sawdust for bedding. Other fine and absorbent materials such as chopped soybean straw or flax chives can work.
  • Add bedding when it begins to stick to the cows. Bedding should be less than 65% moisture.
  • Aerate the pack twice daily, 10 inches deep or deeper, to add oxygen and keep it fluffy.
  • Ventilate the barn well to remove the moisture.
  • Use excellent cow prep at milking time.

What is a compost dairy barn?

Compost-bedded pack barns (compost dairy barns) are an alternative loose housing system for dairy cows. They appear to offer good comfort for lactating, dry and special needs cows.

In general, compost barns have

  • Indoor or outdoor concrete feed alley

  • Bedded pack (resting) area

  • A 4-foot-high wall surrounding the pack

    • Contains one to four walkways for cows and equipment to access the pack

    • Usually made of poured concrete

A compost barn gives cows more room to move than tie stalls or free stalls. These barns may also reduce manure storage costs and space, and save in labor and manure handling.

Compost barns aren’t ideal for every dairy producer. For success, always match the manager with the system.

Barn layout

There’s one key difference between compost dairy barns and freestall dairy barns. Instead of free stalls and freestall alleys, compost dairy barns have a bedded pack area that’s aerated twice daily.

You can lay out compost barns for different feeding practices including:

  • Drive-by feeding (see figure 1)

  • Covered feeding

  • Drive-through feeding with pens on both sides

  • Bunk feeding (inside or outside)


Managing the packed bedding

Compost barn pens start with a 1- to 1.5-foot layer of loose, dry fine wood shavings or sawdust. Add fresh bedding when the pack gets moist enough to stick to the cows after they lie down on it. The bedded area should provide 100 feet per cow of resting space.



Compost dairy barns need good ventilation (air exchange) to:

  • Remove cow moisture and heat.

  • Remove pack moisture and heat from microbial activity.

  • Remove moisture and extend the time between bedding additions in the winter.

High moisture commonly appears as steam rising from the pack during aerating in cold weather. This moisture needs to leave the barn with the ventilation air.

Compost barns should have 16-foot sidewalls for better ventilation. This height also provides access for bedding trucks. The higher sidewall height in a compost barn, compared to a freestall barn, accommodates the sidewall opening lost from the pack walls.

Many compost barns have mixing fans to blow air down onto the pack, which helps dry the surface. Hang the fans high enough to provide head room for aerating equipment at the top pack-height.

Fertilizer value and pack temperatures

In a cross-sectional study we took samples of the pack at two depths. We analyzed these bedding samples for the following.

  • Moisture

  • Ammonia

  • pH

  • Total Carbon (C)

  • Nitrogen (N)

  • Phosphorus (P)

  • Potassium (K)

  • Electrical conductance (soluble salts) concentrations

Table 1 shows the results, which includes a column with recommended values for composting.

The average carbon to nitrogen (C:N) ratio was 19.5:1. A C:N ratio below 25:1 may give off ammonia odor, which may influence the ammonia levels in compost barns.

The average bedding temperature was 108 F. The pack surface temperatures were similar to the surrounding temperature. Temperatures were greater where the pack was fluffier, not as heavily soiled or packed by the cows. This observation was the same with the need for air to promote composting.



    Authors: Marcia Endres, Extension dairy scientist and Kevin Janni, Extension engineer - bioproducts and biosystems engineering

    Reviewed in 2021

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